Snowcat hydrostatic conversion

[ArlyA]

it takes alot of energy to drive tracks. I notice the difference on my honda 450 atv . the sprocket is roughly half the diameter of the tire so it is geared down. 5th gear is practically useless unless on hard packed snow going downhill. and top speed is half of the top speed with tires.

And that's why we have a 1000cc atv. Plus hydrostatic drives waste HP.

 

[trackhead]

Mossroad:agreed on disengagement for start up. Research still in progress.

Arly: I’ve owned a Litefoot hydrostatic cat, a Bombi, tracked UTV, tracked ATV, tracked Samurai. I’m a lunatic and like the building process for some reason. But agreed, don’t want to reinvent the wheel. If I had an extra 80k lying about I’d buy a used PB Scout.

A guy in town built industrial tracked 8x8s for industrial applications and military for 20yrs. He was running 60hp diesel with hydrostatic drive. 3,000lb vehicles. Ultimately I need to sit down with him and figure this out. He’s got decades of building experience and is an engineer.

Still rocking the mechanical drive/CVT but building smaller drive sprockets and might gear the gearbox down a bit further.

 

[trackhead]

it takes alot of energy to drive tracks. I notice the difference on my honda 450 atv . the sprocket is roughly half the diameter of the tire so it is geared down. 5th gear is practically useless unless on hard packed snow going downhill. and top speed is half of the top speed with tires.

Yes, I’ve used/owned every tracked vehicle imaginable. FWIW my current setup is 140hp, it’s geared down from stock 4:1 and has excess power as is due to gear reduction.

 

[trackhead]

Still plows just fine with the arcane brake steer but hydro would be nice. Fun in the yard tonight.

 

[trackhead]

Got the brake steer dialed in might forgo conversion. She’s running great. Thx for prior discussions.

 

[dstig1]

I did some digging in my old reference handbooks and found a table showing drawbar pull per 1000 lbs of vehicle weight on level ground. The chart shows 25 - 37 lbs for snow

Formula to figure axle torque is: T = F x R

T = torque in-lbs
F = drawbar pull in lbs
R = wheel or drive sprocket pitch radius

grade resistance formula: F = GR x W

GR = Grade resistance in percent (20% is .20)
W = gross vehicle weight

Using the above info should allow to calculate required torque at the axles.


Travel Speed: RPM = (336 x MPH) / D

RPM = wheel or drive sprocket RPM
D = wheel or drive sprocket diameter

The above can be used to calculate required hydraulic motor speed.

I just wanted to take a moment to say thanks for all the things you post on hydraulics. You are a great resource to this forum and I for one greatly appreciate it!

 

[oldnslo]

I just wanted to take a moment to say thanks for all the things you post on hydraulics. You are a great resource to this forum and I for one greatly appreciate it!

Thanks for the kind words.